1. Field of the Invention
The present invention relates to a component fitting structure, and more particularly to a structure for fitting the component such as a tensioner unit for automatically adjusting tension of a chain which is wound around a crank sprocket and a cam sprocket to an end of an engine at a side of a crank pulley.
2. Description of the Related Art
As the structures of the type, there have been known such a structure that the tensioner unit is fitted to an end face of a cylinder block or a cylinder head that is a first member at a side of the chain, and then, an end face of the engine in a direction of a crankshaft including a fitting portion of the tensioner unit is covered with a chain cover that is a second member, Such a structure also have been known that the fitting portion of the tensioner unit is provided on an extended portion of a side wall of the cylinder block or the cylinder head and covered with a removable cover.
The former of the above described conventional structures has a drawback that it is likely to deteriorate in assembly, conservaton and maintenance, since the chain cover grows larger in order to cover the tensioner unit and further the entire chain cover must be removed to get access to the tensioner unit. The latter structure has also a drawback that the face of the cylinder block or the cylinder head to be mated with the chain cover expands in a direction of the crankshaft, and accordingly, upsizing of the engine is inevitable.
The invention has been made in order to solve the above described problems of the conventional art. It is an object of the invention to provide a component fitting structure in which the chain cover or a belt cover and the cylinder block or the cylinder head can be minimized without deteriorating in assembling workability and maintainability.
In order to attain such an object, there is provided according to the invention, a component fitting structure which comprises a component fitting hole (25) formed across mated a mated faces between a first member (e.g. a cylinder head 4 in an embodiment or a cylinder block) and a second member (e.g. a chain cover 24 in the embodiment or a belt cover) and a collar (26) fitted in the component fitting hole through a liquid gasket, the component to be fitted (e.g. a tensioner unit 21a in the embodiment) being engaged with the collar.
According to the invention, because the component fitting portion can be provided across the mated faces between the first member and the second member, the members themselves can be made smaller in size as compared with the case where the component is fitted to either one of the members. Moreover, because the collar can be attached in advance to one of these members before the first and the second members are mated together, the fitting portion of the component can be easily observed visually. Further, the component can be removed without separating the two members from each other.
According to a second aspect of the invention, the component fitting hole comprises a semicircular recess formed in the first member and a semicircular recess formed in the second member.
According to a third aspect of the invention, the component to be fitted is engaged with an inner peripheral face of the collar through an O-ring.
According to a fourth aspect of the invention, the collar is provided with a locating pin at a position on an outer peripheral face thereof, the locating pin being fitted in a corresponding hole formed in a bottom face of the recess of the fitting hole.
According to a fifth aspect of the invention, the locating pin is integrally formed with the collar.
According to a sixth aspect of the invention, the mated faces are displaced from a plane passing a center of the component to toward either of the first member and the second member.
According to a seventh aspect of the invention, the mated faces are in alignment with the center of the component to be fitted.
According to an eighth aspect of the invention, there is provided a component fitting structure which comprises a component fitting hole formed across mated contact between a first member and a second member, and a collar fitted in the component fitting hole through a liquid gasket, the component to be fitted being engaged with the collar, the component fitting hole comprising a semicircular recess formed in the first member and a semicircular recess formed in the second member, and the component to be fitted being engaged with an inner peripheral face of the collar through an O-ring.
According to a ninth aspect of the invention, there is provided a component fitting structure which comprises a component fitting hole formed in a cylinder head or a cylinder block as a first member and a chain cover or a belt cover as a second member across mated mated faces therebetween, and a collar fitted in the component fitting hole through a liquid gasket, a tensioner unit as the component to be fitted being engaged with the collar.
According to a tenth aspect of the invention, the component fitting hole comprises a semicircular recess formed in the cylinder head or the cylinder block and a semicircular recess formed in the chain cover or the belt cover.
According to an eleventh aspect of the invention, the tensioner unit is engaged with an inner peripheral face of the collar through an O-ring.
According to a twelfth aspect of the invention, the collar is provided with allocating pin at a position on an outer peripheral face thereof, the locating pin being fitted in a corresponding hole formed in a bottom face of the recess of the fitting hole.
According to a thirteenth aspect of the invention, the locating pin is integrally formed with the collar.
According to a fourteenth aspect of the invention, the mated faces are in alignment with a center of the tensioner unit.
According to a fifteenth aspect of the invention, the mated faces are slightly displaced from a plane passing the center of the tensioner unit toward the cylinder head or the cylinder block.
According to a sixteenth aspect of the invention, the component fitting hole comprises a semicircular recess formed in the cylinder head or the cylinder block and a semicircular recess formed in the chain cover or the belt cover, and an inner peripheral face of the semicircular recess in the chain cover or the belt cover is tangentially extended from a straight line which is parallel to the mated faces.
According to a seventeenth aspect of the invention, fitting bolts of the tensioner unit are fastened at two points in the cylinder head or the cylinder block.
According to an eighteenth aspect of the invention, the cylinder head or the cylinder block is provided with bolting holes along a straight line which is perpendicular to the mated faces and passes the center of the tensioner unit.
According to a nineteenth aspect of the invention, the chain cover is provided with an access hole in order to remove a lock pin for locking an operation of a plunger of the tensioner unit, and a boss including the access hole and a boss around the fitting hole are connected by a rib.
According to a twentieth aspect of the invention, the tensioner unit is fitted to an exterior of a bank of a V-type engine and a single bolting hole is provided in the cylinder head or the cylinder block.